Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The opuE gene from Bacillus subtilis encodes a transport system (OpuE) for osmoprotective proline uptake and is expressed from two osmoregulated promoters: opuE P-1 recognized by the vegetative sigma factor A (sigma A and opuE P-2 dependent on the stress-induced transcription factor sigma B (sigma B). The contributions of these two promoters to osmoregulation of opuE were analysed. Genetic studies using chromosomal opuE-treA operon fusions revealed that opuE transcription is rapidly induced after an osmotic upshock. The strength of opuE expression is proportionally linked to the osmolarity of the growth medium. Deletion analysis of the opuE regulatory region identified a 330 bp DNA segment carrying all sequences required in cis for full and osmoregulated transcription. The proper rotational orientation of the upstream region present within this fragment was essential for the function of both opuE promoters. Mutant opuE-treA fusions with defects in either the sigma A-or the sigma B-dependent promoters revealed different contributions of these sequences to the overall osmoregulation of opuE. opuE P-2 (sigma B) activity increased transiently after an osmotic upshock and did not significantly contribute to the level of opuE expression in cells subjected to long-term osmotic stress. In contrast, transcription initiating from opuE P-1 (sigma A) rose in proportion to the external osmolarity and was maintained at high levels. Moreover, both promoters exhibited a different response to the osmoprotectant glycine betaine in the medium. Our results suggest that at least two different signal transduction pathways operate in B. subtilis to communicate osmotic changes in the environment to the transcription apparatus of the cell.
Mol Microbiol 1998 Jul
PMID:Osmoregulation of the opuE proline transport gene from Bacillus subtilis: contributions of the sigma A- and sigma B-dependent stress-responsive promoters. 970 21

Significant betaine aldehyde dehydrogenase activity was found in porcine kidney. The enzyme was purified 320-fold with an overall recovery of 11%. It had a specific activity of 115.8 nkats/mg protein and proved to be homogeneous by SDS-PAGE with a subunit molecular mass of 52 kDa. IEF studies showed three bands with pI values of 5.74, 5.68 and 5.58, respectively. The enzyme was stable in a pH range between 5.0 and 10.0 and the optimum pH was 9.5. The reaction is highly specific for NAD+ and betaine aldehyde, although acetaldehyde, butyraldehyde and glyceraldehyde can be used. Estimated values of Km at pH 8.0 and 25 degrees C were 127 microM for betaine aldehyde and 40 microM for NAD+. The reaction could not be reversed even at high glycine betaine concentrations. The enzyme was not activated by salts at high concentrations but it was salt tolerant-retaining 50% of maximal activity at 1.0 M K+ and Na+. It is inferred that salt tolerance is an essential property for an enzyme participating in the cellular synthesis of an osmoprotectant. Proline, glycerol, sucrose and mannitol had a little effect on the enzyme activity while glycine betaine had an inhibitory effect.
Comp Biochem Physiol B Biochem Mol Biol 1998 Mar
PMID:Porcine kidney betaine aldehyde dehydrogenase: purification and properties. 973 33

Biosynthesis of the compatible solute glycine betaine in Bacillus subtilis confers a considerable degree of osmotic tolerance and proceeds via a two-step oxidation process of choline, with glycine betaine aldehyde as the intermediate. We have exploited the sensitivity of B. subtilis strains defective in glycine betaine production against glycine betaine aldehyde to select for mutants resistant to this toxic intermediate. These strains were also defective in choline uptake, and genetic analysis proved that two mutations affecting different genetic loci (opuB and opuC) were required for these phenotypes. Molecular analysis allowed us to demonstrate that the opuB and opuC operons each encode a binding protein-dependent ABC transport system that consists of four components. The presumed binding proteins of both ABC transporters were shown to be lipoproteins. Kinetic analysis of [14C]-choline uptake via OpuB (K(m) = 1 microM; Vmax = 21 nmol min-1 mg-1 protein) and OpuC (K(m) = 38 microM; Vmax = 75 nmol min-1 mg-1 protein) revealed that each of these ABC transporters exhibits high affinity and substantial transport capacity. Western blotting experiments with a polyclonal antiserum cross-reacting with the presumed substrate-binding proteins from both the OpuB and OpuC transporter suggested that the expression of the opuB and opuC operons is regulated in response to increasing osmolality of the growth medium. Primer extension analysis confirmed the osmotic control of opuB and allowed the identification of the promoter of this operon. The opuB and opuC operons are located close to each other on the B. subtilis chromosome, and their high sequence identity strongly suggests that these systems have evolved from a duplication event of a primordial gene cluster. Despite the close relatedness of OpuB and OpuC, these systems exhibit a striking difference in substrate specificity for osmoprotectants that would not have been predicted readily for such closely related ABC transporters.
Mol Microbiol 1999 Apr
PMID:Two evolutionarily closely related ABC transporters mediate the uptake of choline for synthesis of the osmoprotectant glycine betaine in Bacillus subtilis. 1021 73

Background: Trinucleotide repeat regions are heritable unstable elements that change in copy number from generation to generation. Amplification of these triplet repeats is an important diagnostic tool for molecular medicine. However, these repeats are often difficult to amplify and may require the use of different cosolvents or amplification strategies. Methods and Results: We used the fragile X and androgen receptor triplet repeat regions to demonstrate a series of conditions that may be used to optimize the amplification of repeat sequences. Conclusions: For androgen receptor, we show that predigestion of the template DNA was sufficient to generate consistent amplification. In the case of fragile X we found that predigestion, when combined with use of betaine as a destabilizing additive, was superior to other methods and yielded consistent amplification of normal and premutation alleles in both isotopic and nonisotopic reactions.
Mol Diagn 1996 Jun
PMID:Strategies for Amplification of Trinucleotide Repeats: Optimization of Fragile X and Androgen Receptor PCR. 1033 Jan 98

Background: The conventional method for diagnosis of fragile X syndrome has been amplification of the trinucleotide repeat region of the FMR-1 gene by polymerase chain reaction (PCR) and Southern blot analysis to detect full expansion and hypermethylation. "Stuttering" resulting from incomplete amplification is still observed in the PCR products despite the use of reagents that reduce the secondary structure of the GC-rich template. In addition, PCR products can be detected by autoradiography only after 1 to 2 days of exposure. By combination of a recently reported amplification protocol with fluorescence detection of PCR products in an automated DNA sequencer, the PCR protocol for amplification of trinucleotide repeats was simplified. This modified protocol is highly reproducible, more accurate, and less costly than the conventional protocol because of the elimination of radioisotopes from the PCR. Methods and Results: PCRs were conducted with betaine and Pfu DNA polymerase. This improved PCR protocol allowed immediate detection of PCR products in agarose gels containing ethidium bromide. Stuttering was completely eliminated and fragments of up to 1kb ( approximately 250 repeats) were visible in agarose gels. PCR products were automatically detected by laser fluorescence in an automated DNA sequencer by inclusion of a fluorescently-labeled primer in the PCR reaction. A short electrophoresis run of 100 minutes in denaturing acrylamide gels was sufficient to give high resolution of fragments with higher accuracy and sensitivity than conventional detection by autoradiography. Conclusions: A simple, nonradioactive protocol that is more rapid and less expensive than the conventional PCR protocol for the detection of trinucleotide repeats has been developed. By use of this detection protocol, fragment sizes containing up to 100 repeats could be detected, alleles differing by one trinucleotide repeat were clearly resolved, and heterogeneous repeat patterns such as those present in mosaics could be discriminated. This protocol has been adapted to the amplification and detection of at least two other classes of trinucleotide repeats [(CAG)(n) and (CTG)(n)], suggesting that it may be a universal protocol for PCR amplification and detection of trinucleotide repeats.
Mol Diagn 1997 Dec
PMID:Automated Detection of Trinucleotide Repeats in Fragile X Syndrome. 1046 18

Fragile X syndrome (FXS) is the most common hereditary form of mental retardation. Molecular analysis of the FMR1 gene has now been applied to diagnosis and carrier detection. Because treatment is not feasible, prevention of FXS by prenatal diagnosis of carrier women early during pregnancy is important. The aim of this pilot study was to ascertain the prevalence of mutant FMR1 gene in normal population of Taiwan and to evaluate the efficacy of a betaine-based polymerase chain reaction (PCR) and nonradioactive Southern blot assays. The DNA was randomly and anonymously collected from 100 women and 100 men. The results showed 62% of the women were heterozygous for the CGG-repeat size in FMR1 gene. One of 300 X chromosomes in this study showed premutation, with 95 CGG repeats. All other chromosomes have CGG repeats ranging from 19 to 52, with eight chromosomes (3%) having more than 40 CGG repeats. The most prevalent allele has 29 repeats (48.1%), followed by 30 (24.0%) and 36 (9.5%), respectively. The results of this study reconfirmed previous reports that the prevalent FMR1 CGG repeat alleles in Chinese population are different from that of other populations. However, the prevalence of premutation gene seems to be comparable among them. The betaine-based PCR could minimize the intrinsic problem of preferential amplification and may reliably determine the different allele repeats in heterozygous females. This nonradioactive Southern blot protocol is safe, efficient, and inexpensive. However, further technical improvement may be needed to be more cost-effective for a wide screening of all pregnant women.
Diagn Mol Pathol 1999 Sep
PMID:Pilot fragile X screening in normal population of Taiwan. 1056 87

ProP is an integral membrane transporter of proline, glycine betaine, and several other osmoprotecting compounds. Fis plus RpoS collaborate to promote a burst of proP transcription in late exponential growth phase. This brief period of ProP synthesis enables stationary phase cells to cope with a potential hyperosmotic shock. Fis activates the RpoS (sigma(38))-dependent proP P2 promoter by binding to a site within the promoter region centered at -41 and thus functions as a class II activator. We show here that activation by Fis at this promoter is completely dependent upon the alpha-CTD of RNA polymerase and that the activation domain on Fis is localized to a four amino acid ridge on the surface of Fis adjacent to the helix-turn-helix DNA binding domain in only one subunit of the homodimer. Fis mutants containing amino acid substitutions within this region are defective in cooperative binding interactions with the sigma(38)-form of RNA polymerase. Some of these substitutions also alter interactions with DNA sequences flanking the core binding site, but we show that changes in Fis-mediated curvature do not affect promoter activity. We conclude that the same amino acids are used by Fis to activate transcription from a class I (-71, rrnB P1) and class II (-41, proP P2) location, but this region is distinct from that required to regulate the Hin site-specific DNA inversion reaction.
J Mol Biol 1999 Nov 26
PMID:Localization of amino acids required for Fis to function as a class II transcriptional activator at the RpoS-dependent proP P2 promoter. 1061 Jul 62

The molecular basis of how rodent nongenotoxic hepatocarcinogens such as phenobarbitone cause liver-tumor formation is poorly understood. An early effect of phenobarbitone exposure is to induce hepatocyte proliferation transiently, and there is evidence that this may be important for subsequent tumor development. In this investigation, we have used the differential display reverse transcriptase polymerase chain reaction technique to analyze differential gene expression in male C57B1/10J mouse liver during the mitogenic phase of the phenobarbitone response. Seventy-seven putative differentially expressed cDNAs were isolated by differential display, and 13 of them were subsequently confirmed as being differentially expressed (both increased and decreased by phenobarbitone). Seven of the cDNAs were homologous to known mouse or human genes (carboxylesterase, coagulation factor X, amine N-sulphotransferase, human protein disulphide isomerase-related protein, cytochrome c oxidase subunit IV, golgin-245, thioredoxin reductase, betaine-homocysteine methyl transferase) and the remainder were novel. The expression pattern of the sulphotransferase was further characterized, and in mouse liver it was found to be significantly induced by phenobarbitone and not by five other rodent nongenotoxic hepatocarcinogens. In summary, the technique has enabled the identification of previously uncharacterized genes whose expression patterns are differentially altered by phenobarbitone in the mouse liver.
J Biochem Mol Toxicol 2000
PMID:Identification of phenobarbitone-modulated genes in mouse liver by differential display. 1063 Apr 19

Very little is known about the molecules regulating the interaction between plants and ectomycorrhizal fungi during root colonization. The role of fungal auxin in ectomycorrhiza has repeatedly been suggested and questioned, suggesting that, if fungal auxin controls some steps of colonized root development, its activity might be tightly controlled in time and in space by plant and/or fungal regulatory mechanisms. We demonstrate that fungal hypaphorine, the betaine of tryptophan, counteracts the activity of indole-3-acetic acid (IAA) on eucalypt tap root elongation but does not affect the activity of the IAA analogs 2,4-D ((2,4-dichlorophenoxy)acetic acid) or NAA (1-naphthaleneacetic acid). These data suggest that IAA and hypaphorine interact during the very early steps of the IAA perception or signal transduction pathway. Furthermore, while seedling treatment with 1-amincocyclopropane-1-carboxylic acid (ACC), the precursor of ethylene, results in formation of a hypocotyl apical hook, hypaphorine application as well as root colonization by Pisolithus tinctorius, a hypaphorine-accumulating ectomycorrhizal fungus, stimulated hook opening. Hypaphorine counteraction with ACC is likely a consequence of hypaphorine interaction with IAA. In most plant-microbe interactions studied, the interactions result in increased auxin synthesis or auxin accumulation in plant tissues. The P. tinctorius / eucalypt interaction is intriguing because in this interaction the microbe down-regulates the auxin activity in the host plant. Hypaphorine might be the first specific IAA antagonist identified.
Mol Plant Microbe Interact 2000 Feb
PMID:Hypaphorine from the ectomycorrhizal fungus Pisolithus tinctorius counteracts activities of indole-3-acetic acid and ethylene but not synthetic auxins in eucalypt seedlings. 1065 5

At high osmotic pressures, mammalian kidney medulla, heart, lens, and brain utilize organic osmolytes to regulate cell volume. However the types and proportions of these solutes vary among tissues in patterns and for non-osmotic roles not fully elucidated. To clarify these, we analyzed osmolyte-type solute contents in rat tissues at 7 and 2 days prenatal and at 0, 7, 14, 21 (weaning), 35 (juvenile) and 77 (adult) days postnatal. Placentas were dominated by betaine, taurine, and creatine, which decreased between the prenatal times. Fetuses were dominated by glutamate and taurine, which increased between the times. In cerebrum, hindbrain and diencephalon, taurine dominated at early stages, but dropped after postnatal day 7, while myo-inositol, glutamine, creatine and glutamate increased after birth, with the latter two dominating in adults. In olfactory bulb, taurine content declined gradually with age and was equal to glutamate in adults. In all brain regions, glycerophosphorylcholine (GPC) reached a peak in juveniles. In postnatal renal medulla, urea, sodium, GPC, betaine, and taurine increased sharply at day 21. Thereafter, most increased, but taurine decreased. In heart, taurine dominated, and increased with age along with creatine and glutamine, while glutamate decreased after postnatal day 7. In lens, taurine dominated and declined in adults. These patterns are discussed in light of hypotheses on non-osmotic and pathological roles of these solutes.
Comp Biochem Physiol A Mol Integr Physiol 2000 Jan
PMID:Developmental changes in organic osmolytes in prenatal and postnatal rat tissues. 1077 30


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>